The eventData property of the
DocumentLoadEvent instance will be a
java.util.Map. For all types in
DocumentLoadEvent the map will contain an entry under
the key "URI" without the quotes. This will be the
fully qualified URI for the event.

For the PROGRESS_URL_LOAD_EVENT_MASK there will be an
entry in the map for the key "message" without the
quotes. This will be the progress message from the browser.